Add support for testing content in SkyView

sky/sdk/lib/framework/layout2.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 library layout;
 
 // This version of layout.dart is an update to the other one, this one using new APIs.
 // It will not work in a stock Sky setup currently.
 
 import 'node.dart';
@@ skipping 698 matching lines @@
     while (child != null) {
       outerHeight += child.getIntrinsicDimensions(innerConstraints).height;
       assert(child.parentData is BlockParentData);
       child = child.parentData.nextSibling;
     }
 
     return new BoxDimensions(width: outerWidth,
                              height: constraints.constrainHeight(outerHeight));
   }
 
-  double _minHeight; // value cached from parent for relayout call
-  double _maxHeight; // value cached from parent for relayout call
+  BoxConstraints _constraints; // value cached from parent for relayout call
   void layout(BoxConstraints constraints, { RenderNode relayoutSubtreeRoot }) {
     if (relayoutSubtreeRoot != null)
       saveRelayoutSubtreeRoot(relayoutSubtreeRoot);
-    relayoutSubtreeRoot = relayoutSubtreeRoot == null ? this : relayoutSubtreeRoot;
+    else
+      relayoutSubtreeRoot = this;
     width = constraints.constrainWidth(constraints.maxWidth);
     assert(width < double.INFINITY);
-    _minHeight = constraints.minHeight;
-    _maxHeight = constraints.maxHeight;
+    _constraints = constraints;
     internalLayout(relayoutSubtreeRoot);
   }
 
   void relayout() {
     internalLayout(this);
   }
 
   void internalLayout(RenderNode relayoutSubtreeRoot) {
-    assert(_minHeight != null);
-    assert(_maxHeight != null);
+    assert(_constraints != null);
     double y = _padding.top;
     double innerWidth = width - (_padding.left + _padding.right);
     RenderBox child = firstChild;
     while (child != null) {
       child.layout(new BoxConstraints(minWidth: innerWidth, maxWidth: innerWidth),
                    relayoutSubtreeRoot: relayoutSubtreeRoot);
       assert(child.parentData is BlockParentData);
       child.parentData.x = _padding.left;
       child.parentData.y = y;
       y += child.height;
       child = child.parentData.nextSibling;
     }
-    height = clamp(min: _minHeight, value: y + _padding.bottom, max: _maxHeight);
+    height = _constraints.constrainHeight(y + _padding.bottom);
     layoutDone();
   }
 
   void hitTestChildren(HitTestResult result, { double x, double y }) {
     defaultHitTestChildren(result, x: x, y: y);
   }
 
   void paint(RenderNodeDisplayList canvas) {
     super.paint(canvas);
     defaultPaint(canvas);
@@ skipping 34 matching lines @@
 
   void setParentData(RenderBox child) {
     if (child.parentData is! FlexBoxParentData)
       child.parentData = new FlexBoxParentData();
   }
 
   BoxConstraints _constraints;  // value cached from parent for relayout call
   void layout(BoxConstraints constraints, { RenderNode relayoutSubtreeRoot }) {
     if (relayoutSubtreeRoot != null)
       saveRelayoutSubtreeRoot(relayoutSubtreeRoot);
-    relayoutSubtreeRoot = relayoutSubtreeRoot == null ? this : relayoutSubtreeRoot;
+    else
+      relayoutSubtreeRoot = this;
     _constraints = constraints;
     width = _constraints.constrainWidth(_constraints.maxWidth);
     height = _constraints.constrainHeight(_constraints.maxHeight);
     assert(height < double.INFINITY);
     assert(width < double.INFINITY);
     internalLayout(relayoutSubtreeRoot);
   }
 
   void relayout() {
     internalLayout(this);
@@ skipping 139 matching lines @@
     canvas.paintChild(body, (body.parentData as BoxParentData).x, (body.parentData as BoxParentData).y);
     if (statusbar != null)
       canvas.paintChild(statusbar, (statusbar.parentData as BoxParentData).x, (statusbar.parentData as BoxParentData).y);
     if (toolbar != null)
       canvas.paintChild(toolbar, (toolbar.parentData as BoxParentData).x, (toolbar.parentData as BoxParentData).y);
     if (drawer != null)
       canvas.paintChild(drawer, (drawer.parentData as BoxParentData).x, (drawer.parentData as BoxParentData).y);
   }
 
 }